Electronic Devices or Components

The following are the commonly used electronic components inside a computer or its peripherals:
Resistor   :
It limits current flow or produces voltage across electrical circuit.It's unit is OHM.
Capacitor :
It stores electrical  change which can be used in circuits.It's unit is Farads(F).
Inductor  :
It opposes the sudden change in the flow of current in circuit. Its unit is Henry(H).
Diode    :
Diode permits current flow in one direction only. It is used in the circuit as an electronic switch / rectifier.
Vacuum Tubes  :
Vacuum tubes were the earliest electronic devices: that were used  in the first generation computers. The early television set also used such tubes. Because of the use of  filament, they generate a lot of heat and consume high power.They were bulky.
Transistors  :
 The vacuum tubes were followed  by transistors. The transistor replaced vacuum tubes in the second generation computers. Transistors were small in size. Transistors does not need filament, so heat generation was extremely less and it consumes less power. Since they were faster and more reliable, therefore used in second generation computers to replace vacuum tubes. It controls the current flow thus is used as an electronic switch.
I.C.(Integrated Circuit)  :
Integrated Circuit also known as chip consists of a number of transistors and their interconnections. The processor built on single chip is known as Micro processor.Using advanced photographic techniques, miniature circuits are produced on the surface of a chip ( a small piece of semi conductor material). The finished network is extremely small which needs a microscope to view the connections. Such a circuit is called  an Integrated Circuit because the components ( Transistors, diodes, resistors ) are an integral part of a chip.